Pressure transmission ratio: is it a reliable parameter in increased urethro-vesical junction mobility?

Our objective was to investigate any correlation between the degree of urethro-vesical junction (UVJ) mobility and the pressure transmission ratio (PTR) values. Five hundred and nineteen patients suffering from stress urinary incontinence were divided into four groups according to their degree of UVJ mobility assessed by the Q-tip test method: group 1 (N = 86), urethral axis at stress (UAS) < 30 degrees; group 2 (N = 191), UAS 31-60 degrees; group 3 (N = 214), UAS 61-90 degrees; and group 4 (N = 28), UAS > 90 degrees. A urethral pressure profile at stress was determined in the supine and standing positions, and PTR was calculated in the middle region of urethral functional length. PTR values for groups 2-4 were compared with those for group 1. In the supine position, the values for groups 3 and 4 were lower than for group 1, while in the standing position, only the values for group 3 were different. The incidence of normal PTR values (i.e., > 90%) was the same in all four groups. Overall correlation between PTR values and degree of UVJ mobility was weak (r = 0.14). We conclude that PTR values does not correlate with UVJ mobility in those patients with a Q-tip test of < 60 degrees. This correlation is inconstant when the Q-tip test was > 60 degrees. Also, 14-30% of patients in all four groups had normal standing PTR values. This may be explained by well-preserved innervation with severe alteration of the anchoring bladder neck structures.